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SubjectRe: [PATCH] VIA timer fix was removed?
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On Mon, Nov 12, 2001 at 03:48:24PM +0100, Andrzej Krzysztofowicz wrote:
> > The following patch (introduced by Vojtech Pavlik some time ago) was
> > removed somewhere between 2.4.14 and 2.4.15-pre3.
> > Without it, the timer counter is reset to a wrong value and
> > gettimeofday() starts to return strange values
> >
> > Nothing aboutit is mentioned in the changelog, so I suppose it wasn't
> > supposed to be removed?
>
> Maybe, it happens because somebody forgot to comment why this code is
> necessary here ?
> Just a guess...

Then perhaps this would be a good idea?

J.

--- linux-2.4.15-pre3/arch/i386/kernel/time.c Sun Nov 11 21:33:31 2001
+++ linux-2.4.15-pre3-new/arch/i386/kernel/time.c Mon Nov 12 14:04:20 2001
@@ -501,6 +501,19 @@

count = inb_p(0x40); /* read the latched count */
count |= inb(0x40) << 8;
+
+ /*
+ * When using some via chipsets (as the vt82c686a, for example)
+ * the system timer counter (i8253) should be reprogrammed in
+ * this case, otherwise it may be reset to a wrong value.
+ */
+ if (count > LATCH-1) {
+ outb_p(0x34, 0x43);
+ outb_p(LATCH & 0xff, 0x40);
+ outb(LATCH >> 8, 0x40);
+ count = LATCH - 1;
+ }
+
spin_unlock(&i8253_lock);

count = ((LATCH-1) - count) * TICK_SIZE;
-
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